Method of making filter element



April 25, 1967 Original Filed May '7, 1962 G. F. PARKER ET AL METHOD OFMAKING FILTER ELEMENT 2 Sheets-Sheet 1 IN VEN TORS GEORGE E PARKER ByandGEORGE E'. SLATER A TTOR/VEY Aprifl 25, 1967 PARKER ET AL 3,315,336

METHOD OF MAKING FILTER ELEMENT Original Filed May 7, 1962 2Sheets-Sheet 2 FIG. 5

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IN VEN TORS GEORGE E PARKER Y and GEORGE E. SLATER A 7' TORNEYS UnitedStates Patent 3,315,336 METHOD OF MAKING FILTER ELEMENT George F.Parker, Cleveland, and George E. Slater, Gates Mills, Ohio, assignors,by mesne assignments, to Rockwell Standard Corporation, a corporation ofDelaware Original application May 7, 1962, Ser. No. 192,654, now

Patent No. 3,261,474, dated July 19, 1966. Divided and this applicationApr. 11, 1966, Ser. No. 541,692

Claims. (Cl. 29163.5)

This is a division of Ser. No. 192,654 filed May 7, 1962 for FilterElement and Method of Making Same issued July 19, 1966 as United StatesLetters Patent No. 3,261,- 474.

This invention relates to filter elements used in liquid or other fluidfilter assemblies and more particularly to a novel method of making thesame.

The filter element of the present invention in its preferred embodimentis composed essentially of a ibendable material such as fine wire meshthat can be crimped, folded or pleated to a desired shape and structurewhich it will maintain. In a preferred method of manufacture, a flatstrip of such material is folded transversely in an accordion patternand then rolled up to form a cylinder, the opposite ends of the rolledstrip being securely and preferably permanently attached together as bywelding, glueing or the like.

This corrugated cylinder is then axially collapsed and spread out toassume an annular disc shape so that one end of the former cylinderforms the inner diameter of the annular disc and the other end isexpanded to form the outer diameter.

The radially corrugated annular disc thus formed is then flattened to acertain depth around the edges of its inner and outer diameters, theseflattened annular rim portions being disposed in different parallelplanes perpendicular to the disc axis. A stiff reinforcing ring is thenclamped over and around the inner flat rim, and two discs provided withsuch inner rings are then placed together in assembly with an aperturedstiff spacer ring interposed between them in axial abutment with therespective reinforcing rings and with the outer flat rims of the discsin axial abutment. An outer stiff reinforcing ring is then clamped overthe abutting outer rims of the two dics to combine the two discs andassociated rings into a relatively stiff disc element.

A series of these disc elements, when suitably placed on the aperturedcenter tube of a filter unit, as will appear, provides a filterarrangement which allows fluid to enter both sides of the discs, passthrough the folded material and along the radial folds through aperturesin the spacer rings in each disc assembly and through aligned holesinto-the center tube. Fluid also flows through the pleat wallssubstantially tangentially of the discs. Fluid flow may, of course, bereversed by passing through the center tube first.

By varying the number and depths of the folds in the disc material aninfinite variety of filter surface areas can be provided and in anyinstance the surface area of the filter disc is considerably increasedas compared to conventional disc filters, especially the so-called edgetype filters. v

Accordingly it'is the main object of the present invention to provide anovel method of making an axially compact filter disc element having anincreased corrugated surface filter area. v 7

An important object of the invention resides in the novel method ofmanufacture wherein a strip of shape retaining filter material such asfine wire mesh is laterally folded to desired corrugations, rolled intoa cylinder, axially flattened to disc shape and formed with inner andouter stiffened rims to provide a relatively stiff self-supportingannular filter disc.

A further object of the invention is the provision of novel method ofmaking crimped filter discs wherein the effective filtering area may beestablished during manufacture by varying the depth and/or number ofcrimped sections.

Another object of the invention resides in the provision of a novelmethod of making a filter disc having increased surface area from anyfoldable, crimpable, or pleatable filter material.

Other objects and novel features of the invention will become apparentfrom the following detailed description in connection with the appendeddrawings in which:

FIGURE 1 is a side elevation partially broken away and in sectionthrough a filter assembly incorporating filter elements made accordingto a preferred embodiment of the invention;

FIGURE 2 is a partial enlarged plan view of a filter element of FIGURE1;

FIGURE 3 is an enlarged diametral section through a filter element ofFIGURE 1;

FIGURE 4 is a sectional view taken substantially along line 44 of FIGURE2 showing the folded material;

FIGURE 5 illustrates a strip of filter material to be folded;

FIGURE 6 is a side elevation of the folded filter material strip;

FIGURE 7 illustrates the folded strip of FIGURE 6 rolled into acylinder;

FIGURE 8 is an end view of the cylinder of FIGURE FIGURES 9 and 10illustrate different parts of the step of axially collapsing thecylinder of FIGURE 7 to form an annular radially corrugated disc; and

FIGURE 11 is an exploded view illustrating assembly of two filter discsinto a filter element.

FIGURE 1 illustrates a filter assembly 20 comprising a rigid housing 21to which is removably secured a filter casing 22 enclosing a space 23.Housing 21 has an inlet opening 24 for introducing gas or other fluidinto a passage 25 that discharges through bottom opening 26 into space23, as indicated by the arrows in FIGURE 1.

Internally housing 22 is formed with a chamber 27 separate from passage25 and communicating with an outlet indicated at 28. A bottom opening 29is provided substantially centrally of the housing in alignment with aboss 31 having a threaded downwardly open bore 32.

A support rod 33 has a threaded upper end 34 received in bore 32, andits lower threaded end 35 extends through a bottom casing opening 36. Anut 37 is mounted on the projecting end of rod 33, and a sealing washer38 is provided over opening 36. With rod 30 rigidly mounted and axiallyfixed in bore 32, When nut 37 is drawn tight it urges casing 22 tightlyagainst the bottom wall of housing 21 with compressed washer 38 sealingthe opening at 36. Usually an annular seal (not shown) is providedbetween the upper edge of casing 22 and the bottom flat wall surface 39of housing 21. Housing 21 is usually a metal casting, and casing 22 isusually a stiff sheet metal stamping.

Rod 33 is surrounded in spaced relation by an axially rigid cylindricalor other tubular metal sleeve 41 that has its upper end in abutmentwithflat surface 39 in surrounding relation to opening 29. A seriesof rowsof apertures 42 are provided in sleeve 41 at equally axially spacedlevels for a purpose to appear. A plurality of annular filter elements43 are axially assembled upon sleeve 41. A rigid locating ring 44 isinterposed between uppermost element 43 and surface 39, and an annularretainer plate 40 axially abuts the lower end of sleeve 41 and thelowermost element 43. A suitable locknut assembly 40 on the Referringparticularly to FIGURES 1-4, each filter element 43 consists essentiallyof two substantially identical but reversed annular filter discs 43a and43]) held in operative assembly.

Filter disc 43a comprises an annulus 45 of fine mesh filter materialsuch as metal wire cloth which will hold a crimped or pleated shapeformed with a series of generally radial corrugations 46 which extendbetween an inner flat annular peripheral rim 47 and an outer fiatannular peripheral rim 48. Rims 47 and 48 are concentric and parallelbut are disposed in axially spaced planes which extend at right anglesto the center line of the element as shown in FIGURE 3. A stiff sheetmetal reinforcing ring 49 of generally U-shape in cross-section isclenched upon and around the inner edge of rim 47.

Filter disc 43b similarly comprises an annulus 51 of the same fine meshfilter material formed with a series of generally radial corrugations 52which extend between an inner fiat annular peripheral rim 53 and anouter flat annular peripheral rim 54. Rims 53 and 54 are concentric andlie in parallel axially displaced planes as in disc 43a, and a stiffsheet metal reinforcing ring 55 of U-shape is clenched upon and aroundthe inner edge of rim 53.

The relatively reversed positions of filter discs 43a and 43b in thefilter element is shown in FIGURE 3 wherein these discs are assembled inconcentric relation with outer rims 48 and 54 in axial surface contact,and the two discs 43a and 43b are secured together in assembly by anouter stiff sheet metal ring 56 which is of generally U-shape andclenched about and along the outer edges of the contacting outer discrims concentric with rings 49 and 55.

The axial space between inner rings 49 and 55 in the filter elementassembly is occupied by a rigid spacer and passage forming ring 57 thatis of about the same diameter and radial width as rings 49 and 55 and isalso of such axial extent as to be tightly clamped between the discs 43aand 43b in the assembly when outer ring 56 is secured in place.

Ring 57 is formed with a series of openings 58 which are at least aslarge as openings 42 in sleeve 41 and of the same circumferentialdistribution as openings 42. It will be noted from FIGURE 3 that theseopenings 58 are in direct communication with the inner ends of all ofthe disc corrugations 46 and 52. As shown in FIGURE 4, the filter discs43a and 43b are preferably so circumferentially disposed that thebottoms of the radial corrugations of the respective discs are adjacentat 60 and define generally radial flow passages 59 as well as providefor generally tangential liquid fiow through the filter element, andalso define opposed external channels 61, thereby providing considerablefilter surface area exposed to the fluid.

Referring back to FIGURE 1, several of these filter elements 43 aremounted within casing 22. The inner diameter of rings 49, 55, 58 is suchthat each filter element 43 slides smoothly onto sleeve 41, and ring 44is of such dimensions that uppermost filter element 43 will be locatedwith its ring passages 58 aligned with sleeve apertures 42. The axialspacing of the aperture rows 42 may be such that all of the apertures 42align with the openings 58 of the respective filter elements When thestack is secured on sleeve 41 by the lock nut assembly. Ring 57 preventsaxial collapse of the inner rims of the filter discs during the mountingon sleeve 41.

After the filter elements 43 are secured to the housing 21, theenclosing casing 22 is mounted.

FIGURES to 11 show the method steps for making the filter discs andassembling them into the filter element.

FIGURES 5 and 6 show a linear strip of filter material 66 which may befine wire clothor any filter material that can be pleated or folded. Thestrip is laterally folded as along lines 68 back and forth to provideaccordion fold pleats or corrugations 70 along its entire length andsymmetrically on both sides thereof. The number of folds and the depthof each fold can be raised to obtain different filter areas. Thiscorrugated strip 66 is then rolled into a cylinder 72 with thecorrugations 70 extending axially as shown in FIGURES 7 and 8. The stripends are welded, glued or otherwise permanently attached as at 74.

The corrugated cylinder 72 is now placed axially around a post on theanvil die 82 of a die press 84 illustrated in FIGURE 9 and carefullyaxially collapsed toward generally annular condition by axial pressureapplied endwise in the direction indicated by the arrows in FIGURE 9.During this collapse the upper edge 86 of cylinder 72 is contracted intoa smaller diameter inner circle, and the lower edge 88 of cylinder 72 isexpanded into a larger diameter outer circle with both circles being inthe same plane when the cylinder is completely collapsed. The lower edge88 slides on smooth flat die surface 89 during this operation.

Completion of the collapsing and stamping operation is illustrated inFIGURE 10. The center post 80 on the anvil die 82 is provided around itsbase with a raised annular flat ledge 90 for a purpose to appear. Theupper die 92 of the die press 84 is provided with a central aperture 94to fit smoothly over the post 80, and the outer periphery of its diecavity 96 is formed with a flat annular shallow ledge 98.

When the dies are closed as in FIGURE 10, corrugated cylinder 72 will becompletely collapsed into a disc 43a (or 43b). The ledge 90 coacts withthe flat bottom surface of cavity 96 to flatten the inner disc peripheryto form the compressed annular inner rim and the ledge 98 coacts withfiat die surface 89 to form the fiat outer rim, and since these ledgesurfaces are in different planes the rims will be formed in axiallydisplaced parallel planes.

This flat forming of the inner and outer disc rims under pressureprovides an annular disc structure wherein the compressed material offiat rims tends to stiffen the entire disc holding the corrugations inplace, and prevent tendency of the disc to return toward its originalcylindrical condition.

The next step is to apply the inner rings 49 and 55 of two of the formeddiscs produced by the operation of FIGURE 10.

Then two of these discs with inner stiffening rings attached arearranged in reversed relation as shown in FIG- URE 11 and broughttogether until the assembly is as shown in FIGURE 3, the clenching ofring 56 about the outer periphery being the final step which holds allof the parts permanently together.

The term substantially radial corrugations used herein is intended todescribe the structure resulting from any mode of forming the filtermaterial such as folding back and forth, fluting, pressing, crimping andthe like, whether accomplished in one operation or in successive lateralbendings along the strip. It will be noted as shown in FIGURE 2 that asa result of the preferred method of manufacture herein disclosed thecorrugations vary in dimensions between the inner and outer peripheriesof the disc, but it is to be understood that the invention is ofsufiicient scope to include filter discs wherein the corrugations may besubstantially of the same dimensions along their lengths and/ or may notlie exactly on radii of the formed disc.

the corrugated filter structure and thus the maximum surface area isalways presented for filtering.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof, andtherefore the preferred embodiment is to be considered in all respectsas illustrative only and not restrictive, the scope of the presentinvention being indicated by the appended claims rather than by theforegoing description.

What is claimed and desired to be secured by Letters Patent is:

1. In a method of making a filter disc, the steps of laterallycorrugating a strip of filter material, joining the ends of said stripto form a cylindrical tubular structure wherein the corrugations arelongitudinal, axially collapsing said tubular structure into an annulardisc wherein the corrugations extend substantially radially, andcompressing the inner and outer peripheries of said annular disc to forminner and outer fiat annular peripheral regions.

2. In the method defined in claim 1, said peripheral regions lying indifferent parallel planes substantially normal to the axis of said disc.

3. In the method of making a filter disc defined in claim 1, the furtherstep of securing a reinforcing ring upon and along said inner peripheralregion.

4. In the method defined in claim 1, said step of laterally corrugatingthe strip being accomplished by accordion folding a strip of saidmaterial.

5. In the method defined in claim 1, said strip of material being ashape retaining wire cloth sheet.

References Cited by the Examiner UNITED STATES PATENTS 2,334,263 11/1943 Hartwell 210494 2,591,056 4/1952 Ericson 29-486 3,017,698 l/l962Hambrecht et al. 29-419 X 3,084,427 4/1963 Holcomb 29-4l9 I OHN F.CAMPBELL, Primary Examiner. THOMAS H. EAGER, Examiner.

1. IN A METHOD OF MAKING A FILTER DISC, THE STEPS OF LATERALLYCORRUGATING A STRIP OF FILTER MATERIAL, JOINING THE ENDS OF SAID STRIPTO FORM A CYLINDRICAL TUBULAR STRUCTURE WHEREIN THE CORRUGATIONS ARELONGITUDINAL, AXIALLY COLLAPSING SAID TUBULAR STRUCTURE INTO AN ANNULARDISC WHEREIN THE CORRUGATIONS EXTEND SUBSTANTIALLY RADIALLY, ANDCOMPRESSING THE INNER AND OUTER PERIPHERIES OF SAID ANNULAR DISC TO FORMINNER AND OUTER FLAT ANNULAR PERIPHERAL REGIONS.